Coal mine transport system

Abstract

The coal mine transportation system comprises a first transportation device, a second transportation device and an overload protection device, the first transportation device comprises a downstream discharge end, the second transportation device comprises an upstream feeding end, the downstream discharge end is located above the upstream feeding end, the upstream feeding end cooperates with the downstream discharge end so that the first transportation device loaded is transferred to the second transportation device, and the overload protection device comprises a material temporary storage assembly, the material temporary storage assembly comprises a material containing box with an open upper end, and the material containing box can move between a first position and a second position in the horizontal direction. The coal mine transportation system has high transportation efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of mining transportation equipment, specifically to a coal mine transportation system. Background Technology

[0002] A scraper conveyor is a device that uses a scraper chain to pull scrapers to transport bulk materials within a trough. Scraper conveyors are widely used in mining faces. In coal mining faces, the scraper conveyor not only transports coal and materials but also serves as the running track for the coal mining machine, making it an indispensable piece of equipment in modern coal mining technology. Continuous operation of the scraper conveyor is essential for normal production. Otherwise, the entire coal mining face will be shut down, causing a production interruption. However, the amount of coal transported by a scraper conveyor is not uniform, which can easily overload downstream conveyors. Furthermore, operators need time to stop or slow down the scraper conveyor, leading to overload damage to downstream conveyors and resulting in low transportation efficiency. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, this invention proposes a coal mine transportation system with high transportation efficiency.

[0005] The coal mine transportation system of this invention includes: a first transportation device, the first transportation device including a downstream discharge end; a second transportation device, the second transportation device including an upstream feed end, the downstream discharge end being located above the upstream feed end, the upstream feed end cooperating with the downstream discharge end to transfer the material loaded by the first transportation device to the second transportation device; and an overload protection device, the overload protection device including a material storage component, the material storage component including a material receiving box with an open upper end, the material receiving box being movable between a first position and a second position relative to each other in the horizontal direction, the material receiving box located at the first position being able to collect the material falling from the downstream discharge end, and the material receiving box moving to the first position when the motor current value of the second transportation device is greater than or equal to a first preset value.

[0006] The coal mine transportation system of this invention can move the material receiving box to a position below the downstream discharge end to temporarily store unloaded material when the motor current value of the second transportation device is greater than or equal to a first preset value. This prevents material from continuing to fall onto the second transportation device, allowing the second transportation device a certain amount of time to unload a portion of the transported material, preventing overload damage to the second transportation device, and avoiding significant impact on material transportation. Therefore, the coal mine transportation system of this invention has high transportation efficiency.

[0007] Therefore, the coal mine transportation system of this invention has high transportation efficiency.

[0008] In some embodiments, the material receiving box includes: a box body defining a receiving groove; a filter grid disposed in the receiving groove, the filter grid dividing the receiving groove into an over-screen area and an under-screen area opposite each other in the vertical direction, the under-screen area being located below the over-screen area, and the box body further includes a first discharge port disposed on the wall surface of the under-screen area.

[0009] In some embodiments, the material storage assembly further includes: a support, the support having a guide rail extending in the same direction as the horizontal direction, the housing having a sliding member cooperating with the guide rail to allow the housing to move along the horizontal direction; and a drive assembly including a first telescopic rod whose dimensions in the horizontal direction are variable, one end of the first telescopic rod being connected to the housing in the horizontal direction, and the other end of the first telescopic rod being connected to the support.

[0010] In some embodiments, the overload protection device further includes: a current detection sensor and a first data processor, the current detection sensor being electrically connected to the second transport device, and the current detection sensor being used to detect the motor current of the second transport device.

[0011] In some embodiments, the current detection sensor and the first data processor are electrically connected so that the current detection sensor sends a detected current detection signal to the first data processor. The first data processor is electrically connected to the first telescopic rod. When the motor current value of the second transport device is greater than or equal to a first preset value, the first data processor transmits a first action signal to the first telescopic rod so that the first telescopic rod moves the material container to the first position.

[0012] In some embodiments, the filter grid includes a first end and a second end, the filter grid is rotatably disposed in the receiving groove such that the first end of the filter grid is located above the second end, the housing further includes a second discharge port disposed on the inner wall surface of the screen area, and the second discharge port is adjacent to the second end on the side in the direction from the first end to the second end.

[0013] In some embodiments, the first end is rotatably connected to the inner wall of the receiving groove, and the material temporary storage assembly further includes a second telescopic rod, the second telescopic rod having a variable dimension in the vertical direction, the upper end of the second telescopic rod being rotatably connected to the second end, and the lower end of the second telescopic rod being rotatably connected to the first end.

[0014] In some embodiments, the material storage assembly further includes: a second data processor and a pressure sensor, the pressure sensor being mounted on the bracket and capable of cooperating with the housing to detect the weight data of the housing, the second data processor being electrically connected to the pressure sensor, and when the weight data of the housing is greater than a second preset value, the second data processor transmitting a second action signal to the second telescopic rod to raise the first end of the second telescopic rod.

[0015] In some embodiments, the coal mine transportation system further includes a third transportation device, the third transportation device including a feeding section and a discharging section, the feeding section cooperating with the second discharge port, and the discharging section cooperating with the second transportation device, so that the third transportation device transports the material in the over-screen zone to the second transportation device.

[0016] In some embodiments, the coal mine transportation system further includes: an alarm device electrically connected to the current detection sensor, the alarm device being able to issue an alarm signal when the motor current value of the second transportation device is greater than or equal to a first preset value. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a coal mine transportation system according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of a coal mine transportation system according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the structure of the material container box according to an embodiment of the present invention.

[0020] Figure label:

[0021] 100. Coal mine transportation system; 1. First conveying device; 11. Downstream discharge end; 2. Second transport device; 21. Upstream feed end; 3. Overload protection device; 31; Material storage assembly; 311. Material receiving box; 3111. Box body; 3112. Over-screen zone; 3113. Under-screen zone; 3114. First discharge port; 3115. Second discharge port; 312. Filter grid; 312. Support; 313. Guide rail; 314. First telescopic rod; 315. Second telescopic rod; 4. Third transport device; 41. Feeding section; 42. Discharge section. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] The coal mine transportation system 100 of the present invention is described below with reference to the accompanying drawings.

[0024] like Figures 1-3 As shown, the coal mine transportation system 100 of this embodiment includes: a first transportation device 1, a second transportation device 2, and an overload protection device 3.

[0025] The first conveying device 1 includes a downstream discharge end 11 and is suitable for transporting coal. The first conveying device 1 can be a scraper conveyor. The second conveying device 2 includes an upstream feed end 21, and the downstream discharge end 11 is located above the upstream feed end 21. The upstream feed end 21 and the downstream discharge end 11 cooperate to transfer the material loaded by the first conveying device 1 to the second conveying device 2. In other words, the material transported by the first conveying device 1, after falling from its downstream discharge end 11, can fall onto the upstream feed end 21 of the second conveying device 2, so that the second conveying device 2 can continue to transport the material.

[0026] The overload protection device 3 includes a material storage assembly 31, which includes a material receiving box 311 with an open upper end. The material receiving box 311 is movable between a first position and a second position in the horizontal direction. The material receiving box 311 in the first position can collect at least a portion of the material falling from the downstream discharge end 11. When the motor current value of the second conveying device 2 is greater than or equal to a first preset value, the material receiving box 311 moves to the first position. The first preset value is the overload current value of the motor of the second conveying device 2; or, the first preset value is less than the overload current value of the motor of the second conveying device 2, for example, the overload current value of the motor of the second conveying device 2 is 180A, and the first preset value is 175A.

[0027] It should be noted that the first preset value needs to be determined based on the specific type and model of the second transport device 2 and the transport conditions, and is not limited here.

[0028] The specific implementation process of the coal mine transportation system 100 according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0029] When the motor current of the second transport device 2 is less than the first preset value, the material is transported from the upstream end of the first transport device 1 to the downstream end of the first transport device 1. The material located at the downstream end of the first transport device 1 falls downward and detaches from the first transport device 1. The fallen material lands at the upstream feed end 21 of the second transport device 2, allowing the second transport device 2 to continue transporting the material.

[0030] When the motor current of the second transport device 2 is greater than or equal to the first preset value, the material receiving box 311 moves from the second position to the first position, so that all the material falling from the downstream end of the first transport device 1 falls into the material receiving box 311, thereby preventing the load on the second transport device 2 from continuing to increase and preventing overload damage to the second transport device 2. When the motor current of the second transport device 2 is less than the first preset value, the material receiving box 311 moves to the second position, so that the material falling from the first transport device 1 can fall back onto the second transport device 2, allowing the second transport device 2 to continue transporting.

[0031] In related technologies, when a downstream conveyor is overloaded, operators need to shut down the scraper conveyor or reduce its speed. However, slowing down the scraper conveyor takes time, during which a significant amount of material will still fall onto the downstream conveyor, posing a continued risk of overload. Furthermore, since multiple supporting coal mining equipment are located upstream of the scraper conveyor, directly shutting it down would severely impact the operation of the entire coal mining system, significantly affecting its operational efficiency.

[0032] Compared with related technologies, the coal mine transportation system 100 of this embodiment of the invention can move the material receiving box 311 to the lower part of the downstream discharge end 11 to temporarily store the falling material when the motor current value of the second transportation device 2 is greater than or equal to a first preset value. This prevents the material from continuing to fall on the second transportation device 2, allowing the second transportation device 2 a certain amount of time to unload a portion of the transported material, preventing the second transportation device 2 from being overloaded and damaged, and avoiding significant impact on the transportation of materials. Therefore, the coal mine transportation system 100 of this embodiment of the invention has high transportation efficiency.

[0033] Therefore, the coal mine transportation system 100 of this embodiment of the invention has high transportation efficiency.

[0034] To make this application easier to understand, the coal mine transportation system 100 of this invention will be further described below, taking the horizontal direction and the left and right direction as an example.

[0035] In some embodiments, such as Figures 2-3 As shown, the material receiving box 311 includes a box body 3111 and a filter grid 312. The box body 3111 defines a receiving groove; the filter grid 312 is disposed in the receiving groove. The filter grid 312 divides the receiving groove into an over-screen zone 3112 and an under-screen zone 3113 that are opposite each other in the vertical direction. The under-screen zone 3113 is located below the over-screen zone 3112. The box body 3111 also includes a first discharge port 3114, which is disposed on the wall of the under-screen zone 3113.

[0036] The material discharged at the downstream discharge end 11 falls into the receiving trough for temporary storage. During this process, the material first falls into the over-screen zone 3112, where it is screened by the filter grid 312, allowing smaller particles to pass through and fall into the under-screen zone 3113. The smaller particles then fall through the first discharge port 3114 onto the upstream feed end 21 of the second conveying device 2, where they are transported by the second conveying device 2.

[0037] Understandably, while the material receiving bin 311 is collecting the falling material, the second conveying device 2 continues its transport operation, continuously unloading a portion of the material. By screening a portion of the falling material through a grid screen, smaller particles fall onto the second conveying device 2 for continuous transport. This not only prevents the second conveying device 2 from overloading but also prevents the material receiving bin 311 from collecting too much material, thus avoiding overflow. Furthermore, it ensures continuous and uninterrupted material transport, minimizing the impact on material transport efficiency.

[0038] In some embodiments, such as Figures 1-2 As shown, the material storage assembly 31 also includes a support 312 and a drive assembly. The support 312 is equipped with a guide rail 313, the extension direction of which is consistent with the left-right direction. The housing 3111 is equipped with a sliding member that cooperates with the guide rail 313 to allow the housing 3111 to move in the left-right direction. The drive assembly includes a first telescopic rod 314, the size of which is variable in the left-right direction. One end of the first telescopic rod 314 in the left-right direction is connected to the housing 3111, and the other end is connected to the support 312. In other words, by extending and retracting the first telescopic rod 314 in the left-right direction, the material storage housing 311 can move in the left-right direction, allowing the material storage housing 311 to collect materials in a timely manner. This design is not only simple in structure but also convenient to use.

[0039] In some embodiments, such as Figures 1-2As shown, the overload protection device 3 further includes a current detection sensor and a first data processor. The current detection sensor is electrically connected to the second transport device 2 and is used to detect the motor current of the second transport device 2. In other words, the monitoring of the motor of the second transport device 2 is achieved through the current detection sensor, which is not only accurate but also sensitive, allowing operators to take timely action when the motor current value of the second transport device 2 is greater than or equal to a first preset value. Therefore, the practicality of the coal mine transport system 100 of this embodiment of the invention is improved.

[0040] Furthermore, the current detection sensor and the first data processor are electrically connected, so that the current detection sensor sends the detected current detection signal to the first data processor, and the first data processor is electrically connected to the first telescopic rod 314. When the motor current value of the second transport device 2 is greater than or equal to a first preset value, the first data processor transmits a first action signal to the first telescopic rod 314, so that the first telescopic rod 314 drives the material receiving box 311 to move to the first position.

[0041] The current detection sensor transmits the detected current detection signal to the first data processor in real time. When the current detection signal is greater than or equal to a first preset value, the first data processor transmits a first action signal to the first telescopic rod 314 to command the first telescopic rod 314 to extend to the right, thereby moving the material receiving box 311 to the right to a first position so that the material receiving box 311 can collect the material dropped from the first transport device 1.

[0042] In addition, when the current detection signal is less than the first preset value, the first data processor transmits a third action signal to the first telescopic rod 314 to command the first telescopic rod 314 to retract to the left, thereby moving the material container 311 to the left to the second position.

[0043] The first data processor controls the first telescopic rod 314 to extend and retract based on the current detection signal, thereby controlling the material receiving box 311 to move in the left and right directions, thus realizing automatic control of the overload protection device 3. Therefore, it not only greatly reduces the labor intensity of operators but also provides a more sensitive response and higher work efficiency.

[0044] In some embodiments, such as Figure 3 As shown, the filter grid 312 includes a first end and a second end. The filter grid 312 is rotatably disposed in a receiving groove such that the first end of the filter grid 312 is located above the second end. The housing 3111 also includes a second discharge port 3115, which is disposed on the inner wall surface of the screen area 3112, and the second discharge port 3115 is located on the side adjacent to the second end in the direction from the first end to the second end (e.g., Figure 3(at the rear of the middle). In other words, by rotating the filter grid 312, the filter grid 312 tilts towards one side of the second discharge port 3115, and the remaining material placed on the filter grid 312 is discharged from the receiving trough through the second discharge port 3115. This makes it easier to remove the remaining material placed on the filter grid 312 from the receiving cavity, thus further improving the practicality of the coal mine transportation system 100 of this embodiment of the invention.

[0045] Furthermore, the first end is rotatably connected to the inner wall of the receiving tank. The material storage assembly 31 also includes a second telescopic rod 315, the dimensions of which are variable in the vertical direction. The upper end of the second telescopic rod 315 is rotatably connected to the second end, and the lower end of the second telescopic rod 315 is rotatably connected to the first end. In other words, by extending the second telescopic rod 315 in the vertical direction, the second end of the filter grid 312 is raised, allowing the filter grid 312 to tilt and discharge the material it carries through the second discharge port 3115. After the material is discharged, the second telescopic rod 315 is retracted to lower the second end, thereby restoring the filter grid 312 to its original position. This design is not only simple in structure but also convenient in operation.

[0046] In some embodiments, such as Figure 3 As shown, the material storage assembly 31 further includes a second data processor and a pressure sensor. The pressure sensor is mounted on the bracket 312 and can cooperate with the housing 3111 to detect the weight data of the housing 3111. The second data processor is electrically connected to the pressure sensor. When the weight data of the housing 3111 is greater than a second preset value and the current detection data is less than a first preset value, the second data processor transmits a second action signal to the second telescopic rod 315 to raise the first end of the second telescopic rod 315.

[0047] In other words, when the material in the receiving tank accumulates to a weight exceeding the second preset value, the second data processor transmits a second action signal to the second telescopic rod 315, causing the second telescopic rod 315 to extend and tilt the filter grid 312, thus dumping a portion of the material out of the second discharge port 3115. Furthermore, when the weight is less than the second preset value, the second data processor transmits a fourth action signal to the second telescopic rod 315, causing the second telescopic rod 315 to retract and restore the filter grid 312 to its original position. This achieves automatic control of the filter grid 312. Therefore, it not only significantly reduces the labor intensity of operators but also provides a more sensitive response and higher work efficiency. It should be noted that the second preset value needs to be determined based on specific working conditions and is not limited here.

[0048] Furthermore, the coal mine transportation system 100 of this embodiment further includes: a third transportation device 4, which includes a feeding section 41 and a discharging section 42. The feeding section 41 cooperates with a second discharge port 3115. The discharging section 42 cooperates with the second transportation device 2 so that the third transportation device 4 transports the material in the oversize zone 3112 to the second transportation device 2. Thus, the material discharged from the second discharge port 3115 is transported to the second transportation device 2 by the third transportation device 4.

[0049] When the weight of the housing 3111 exceeds the second preset value and the current detection data is less than the third preset value, the third conveying device 4 operates and transports the material discharged from the second outlet 3115 to the second conveying device 2. This ensures that the second conveying device 2 is not overloaded, allowing the material discharged from the second outlet 3115 to be transported to the second conveying device 2, so that the second conveying device 2 can continue to transport the material to the predetermined position. This further reduces the impact on transportation efficiency.

[0050] In some embodiments, the coal mine transportation system 100 of this invention further includes: an alarm device electrically connected to a current detection sensor, capable of issuing an alarm signal when the motor current value of the second transportation device 2 is greater than or equal to a first preset value. The alarm device can be a loudspeaker; or, the alarm device can be a light generator; or, the alarm device can be other types of alarm devices. This allows the alarm device to issue an alarm signal to the outside world, enabling operators to take timely action.

[0051] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0053] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0055] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A coal mine transportation system, characterized in that, include: A first transport device, the first transport device including a downstream discharge end; The second transport device includes an upstream inlet end and a downstream outlet end located above the upstream inlet end. The upstream inlet end and the downstream outlet end cooperate to transfer the material loaded on the first transport device to the second transport device. An overload protection device includes a material storage component, which includes a material receiving box with an open upper end. The material receiving box is movable between a first position and a second position in the horizontal direction. The material receiving box at the first position can collect the material falling from the downstream discharge end. When the motor current value of the second transport device is greater than or equal to a first preset value, the material receiving box moves to the first position; when the motor current value of the second transport device is less than the first preset value, the material receiving box moves to the second position, so that the material falling on the first transport device can fall back onto the second transport device, allowing the second transport device to continue transporting. The material container includes: a container body, the container body defining a receiving slot; A filter grid is disposed in the receiving tank, which divides the receiving tank into an over-screen area and an under-screen area that are opposite each other in the vertical direction. The under-screen area is located below the over-screen area. The housing also includes a first discharge port, which is disposed on the wall of the under-screen area. The material discharged from the downstream outlet falls into the receiving trough to temporarily store the material. During this process, the material first falls into the screen area and is screened by the filter grid, so that the smaller particle size material can pass through the filter grid and fall into the screen area. The smaller particle size material then falls into the upstream feed end of the second conveying device through the first discharge port, and is thus transported by the second conveying device.

2. The coal mine transportation system according to claim 1, characterized in that, The material storage assembly further includes: a support, a guide rail on the support, the extension direction of the guide rail being consistent with the horizontal direction, and a sliding member on the box body, the sliding member cooperating with the guide rail to allow the box body to move along the horizontal direction; A drive assembly includes a first telescopic rod whose dimensions are variable in the horizontal direction. One end of the first telescopic rod in the horizontal direction is connected to the housing, and the other end of the first telescopic rod in the horizontal direction is connected to the bracket.

3. The coal mine transportation system according to claim 2, characterized in that, The overload protection device further includes: a current detection sensor and a first data processor, wherein the current detection sensor is electrically connected to the second transport device and is used to detect the motor current of the second transport device.

4. The coal mine transportation system according to claim 3, characterized in that, The current detection sensor is electrically connected to the first data processor so that the current detection sensor sends a detected current detection signal to the first data processor. The first data processor is electrically connected to the first telescopic rod. When the motor current value of the second transport device is greater than or equal to a first preset value, the first data processor transmits a first action signal to the first telescopic rod so that the first telescopic rod moves the material container to the first position.

5. The coal mine transportation system according to any one of claims 2-4, characterized in that, The filter grid includes a first end and a second end. The filter grid is rotatably disposed in the receiving groove such that the first end of the filter grid is located above the second end. The housing also includes a second discharge port, which is disposed on the inner wall surface of the screen area and is located adjacent to the second end in the direction from the first end to the second end.

6. The coal mine transportation system according to claim 5, characterized in that, The first end is rotatably connected to the inner wall of the receiving tank. The material temporary storage assembly also includes a second telescopic rod. The size of the second telescopic rod in the vertical direction is changeable. The upper end of the second telescopic rod is rotatably connected to the second end, and the lower end of the second telescopic rod is rotatably connected to the first end.

7. The coal mine transportation system according to claim 6, characterized in that, The material storage assembly further includes a second data processor and a pressure sensor. The pressure sensor is mounted on the bracket and can cooperate with the housing to detect the weight data of the housing. The second data processor is electrically connected to the pressure sensor. When the weight data of the housing is greater than a second preset value, the second data processor transmits a second action signal to the second telescopic rod to raise the first end of the second telescopic rod.

8. The coal mine transportation system according to claim 6 or 7, characterized in that, The device further includes a third transport device, which comprises a feeding section and a discharging section. The feeding section cooperates with the second discharge port, and the discharging section cooperates with the second transport device, so that the third transport device transports the material in the over-screen zone to the second transport device.

9. The coal mine transportation system according to claim 3 or 4, characterized in that, Further includes: An alarm device is electrically connected to the current detection sensor, and the alarm device can issue an alarm signal when the motor current value of the second transport device is greater than or equal to a first preset value.

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